var isDone = false;
var a1 = 10;
var a2 = 5;
var myName = 'Tom';
var myAge = 19;
var info = "My name is ".concat(myAge, ", I am ").concat(myAge, " years old");
var u = undefined;
var n = null;
var list1 = [1, 2, 3];
var list2 = [1, 2, 3];
var t1;
t1 = ['java', 10];
console.log(t1[0].substring(1));
// enum Color{
//     Red,Green,Blue
// }
var Color;
(function (Color) {
    Color[Color["Red"] = 1] = "Red";
    Color[Color["Green"] = 2] = "Green";
    Color[Color["Blue"] = 3] = "Blue";
})(Color || (Color = {}));
var myColor = Color.Blue;
console.log(myColor, Color.Green);
var colorName = Color[1];
console.log(colorName);
var notSure = 4;
notSure = 'maybe a string';
notSure = false;
var list = [1, true, 'free'];
list[1] = 100;
/* 表示没有任何类型, 一般用来说明函数的返回值不能是undefined和null之外的值 */
function fn() {
    console.log('fn()');
    // return undefined
    // return null
    // return 1 // error
}
var unusable = undefined;
